The methods to synthesize and alter the color of diamonds are developing at a rate we could call “dizzying.” We are seeing how, day by day, synthetic diamonds and treated diamonds to improve their color is reaching all areas of jewelry, from manufacturing to wholesale and retail jewelry and gemstone trade. Through wholesale diamond merchants, synthetic and treated diamonds enter the jewelry production chain and eventually reach the consumer. In principle, this does not constitute a problem because these types of gems must be marketed at all times as such, that is, treated or synthetic gems. But it can happen, and sometimes it happens, that some merchants, either because they do not know their origin or pink diamond research, even by a fraudulent operation, when selling this type of synthetic or treated gems do not indicate these fundamental data from multiple points of view, one of them the Price: natural stones always have a higher price.
Currently, gemological laboratories are equipped to identify these gems. In the same way that the methods of synthesis and the treatments to alter the color have evolved, the instruments and techniques to detect them have also followed this rhythm. Today, in general, in most cases we can detect diamonds that have been treated by radiation and high temperatures and pressures. However, sometimes, when the gems are very small the work is more complicated than when we deal with gems of a certain size because they are more manageable.
Let’s see a case study with some copies that we extracted, at the request of our client, of three batches of “fancy” colored diamonds whose origin according to their supplier was natural, but which turned out to be natural diamonds treated to improve their color.
The average color of the diamonds in a lot was deep dark yellow or dark yellow; another lot contained greenish-yellow diamonds of medium tone and intense saturation; and, the third lot had brownish pink diamonds with a light-medium tone. We take 5, 8 and 16 copies respectively of each lot. The size ranged between 2.50 (0.07 ct) and 1.40 mm (0.01).
The behavior of the dark pink diamonds followed a similar tonic, 9 diamonds had fluorescence, of them 4 greenish-yellow and 5 bluish-white, and none had fluorescence. With ultraviolet light of short wave the same, but one of them had strong phosphorescence.
We must emphasize that the fluorescence of the diamonds we are studying, in no case, seemed to follow specific crystallographic directions. This data is important because of the fluorescence of yellow diamonds synthesized by high temperatures and pressures follows crystallographic directions parallel to the cube face.
In summary, the fluorescence of the specimens was stronger with long-wave ultraviolet light than with short wave and yellow-green fluorescence predominated. This behavior is like that of the yellow and yellow-greenish diamonds HPHT treated that we can see documented in several gemological articles, among them we highlight the laboratory note of the journal Gem and Gemology.